Do not re-use IDs for the various assets in the DB

Re-use of IDs makes it very difficult to write integrations sanely. Example shared on slack:

1. need storage, please create and share
   dataset A is created
   dataset A is shared with nfs ID 1

2. it's time to tear down A as an high-level asset (remove share and dataset)
   share 1 is removed
   dataset A is attempted to delete, but fails for whatever reason

3. before a retry is attempted someone else needs new storage
   dataset B is created
   dataset B is shared with nfs ID 1

4. lets retry the delete of A
   make sure nfs share ID 1 is gone..nope still there
   share 1 is removed (oops, that was for something else now)
   dataset A is deleted

dataset B is no longer shared.

I've specifically seen re-use with smb/nfs and the various iscsi assets.